Number the Stars is a story that honestly approaches the tragedy of the Holocaust and uses the events of the war to show humanity's potential for courage and decency. In the weeks following the Jewish High Holidays in 1943, nearly seven thousand of Denmark's Jews were smuggled across the sea to Sweden. Lowry does not talk about the Nazi concentration camps or the Jews' struggles elsewhere in Europe.

Instead, she chooses to focus on one country—and one particular set of characters—in order to emphasize that ordinary people were involved in the Resistance movement. The Johansens are willing to let Annemarie risk her life to carry the handkerchief to Uncle Henrik. Mother and daughter learn the importance of acting on their beliefs rather than waiting for others to act for them.